Retention method for flexible seating material

ABSTRACT

An upholstered patio chair having a metal frame structure of compound three-dimensional shape with at least one internal hollow channel extending along the length of the frame structure and an elongated groove located in the frame structure opening into the hollow channel and forming a lip portion in the frame structure. At least one fabric panel for upholstering the frame which includes an edge containing a loop which extends through the elongated groove and into the hollow channel of the frame structure. An elongated wedge member secures the edge of the fabric panel to the frame structure in the channel by creating an interference fit between the wedge member and the lip portion of the frame structure.

FIELD OF THE INVENTION

[0001] This invention relates generally to outdoor patio furniture and,more particularly to a technique for upholstering a chair comprising awelded extruded metal frame and an upholstery material fabric attachedto the frame so the fabric material is kept in tension as the materialis assembled onto a compound contour of the frame.

BACKGROUND OF THE INVENTION

[0002] Outdoor patio furniture has become a highly competitive market inwhich manufacturers are always looking for ideas that cut down onmanufacturing costs and time, as well as providing a superior product.The present invention is a retention method for a fabric seatingmaterial that is captured along the complete perimeter of a chair frame.Because patio furniture is designed to remain outdoors, typically thefurniture is constructed of metal or plastic. Plastic has proven to bean undesirable material because it tends to have a short service life.Metal, on the other hand, is more desirable in that it is able towithstand the elements and lasts for generations.

[0003] A problem with metal outdoor patio furniture is that it can beuncomfortable to be seated on for an extended length of time, unless theseating surfaces are designed properly. Typically, when people are usingpatio furniture, it is during a time of leisure and therefore acomfortable seating surface is desirable.

[0004] Manufacturers of metal outdoor furniture have designed thefurniture to incorporate cushions to make the furniture morecomfortable. However, cushions can be inconvenient because they must bestored indoors to protect them from the elements such as rain andprolonged sun exposure. Not only is it inconvenient to remove thecushions after each use, but cushions themselves can require additionalstorage space when not in use.

[0005] Recognizing the problems associated with metal outdoor patiofurniture and the problems created by the use of cushions, manufacturershave looked for a way to upholster patio chairs with a material that iscomfortable yet will not require its removal and storage when not inuse. It has become apparent that a woven synthetic fabric is an idealmaterial for use with outdoor metal patio furniture. This materialpossesses qualities of providing a comfortable seating surface whilebeing water resistant and therefore able to withstand the outdoorenvironment.

[0006] A problem faced by manufacturers of outdoor patio furniture ishow to attach the synthetic fabric to a metal frame structure. Thematerial has to be secured to the frame in such a way that it provides aseating and back surface strong enough to support the user whileproviding a comfortable surface. Use of fasteners such as staples orrivets is not necessarily desirable or practical for certain types ofmetal frame outdoor patio furniture.

[0007] The patio furniture industry has in recent years used a methodfor attaching woven synthetic fabric to a metal frame structure whichhas proved to be highly successful. This technique includes the step offolding over the edges of the fabric and stitching the edge down to forma loop along opposite sides of the fabric. These loops are then attachedto the sides of the frame structure by inserting them in a groove alongthe surface of the hollow frame, such that the loop extends through thecenter of a hollow channel in the frame members. A flexible plastic rodhaving a diameter larger than the width of the groove is threadedthrough the channel and the loop within the frame, thereby securing thefabric to the frame members along its entire length. This technique hasbeen used to secure fabric to the seating surface as well as the backsurface of the chair. It is recognized that this technique provides areasonably comfortable seating surface, however, this method has beenlimited to use on chairs having simple two dimensional seating and backsurfaces. Considering that prior seating attachment design relies on aframe having a slot with a fixed width that is smaller than the size ofthe rod, requires that the fabric hem be inserted into the slot firstwithout the rod and then the rod must be passed through an opening atthe end of the frame through the hem. This method requires the fabric tobe in a non-tension condition during assembly and other mechanical meansare needed to spread the frame in such a way as to put tension in thefabric.

[0008] It has also been recognized that outdoor patio furniture could beeven more comfortable if designed to incorporate a compoundthree-dimensional contour, thereby conforming better to the contours ofthe human body. A compound surface is created by changing the directionof the fabric in a third dimension, for example, by covering the frameat the third and fourth sides. Additionally, chairs incorporating such acompound three-dimensional contour can be aesthetically more appealing.Thus, there exists a need for a method for upholstering outdoor patiofurniture which incorporates compound three-dimensional contours andeliminates the problems with previous fabric retention methods.

SUMMARY OF THE INVENTION

[0009] The present invention provides an upholstered outdoor patioseating furniture having compound three-dimensional contours and aretention method for the flexible seating material. The patio chair andretention method of the present invention result in a strong design tohold the fabric in place under high tension, is easy to install in theframe, and is able to provide a flexible seating surface on a compoundframe structure which results in an appearance that the flexible seatingis an integral part of the frame. This invention facilitates a fullperimeter fabric attachment since side openings are not needed to inserta rod and tensioning hardware is not needed. Tensioning methods for foursides would be very complex and costly with previous methods and areeliminated by the present invention.

[0010] In one embodiment, the chair comprises a rigid metal framestructure in which frame members are preferably made of extruded metalhaving a cross-section which includes one or more internal cavitiesextending lengthwise along the frame member. The frame members areassembled in a desired design configuration to form a frame structureenclosed on all sides and defining the contours of a right side, a leftside, a back surface and a seating surface. One or more of each sidesurface, back surface and seating surface is formed such that a compoundthree-dimensional contour for the chair is created by the fabric.

[0011] Each section of the frame to which the flexible seating materialis to be attached includes a groove in the frame which extends into thehollow interior of the cross-sectional structure of the frame member.This groove is used to attach the flexible material to the framestructure. An elongated narrow loop is formed along edges of the fabricseating surface which is to be attached to the frame member. Plasticrods are then inserted into the loop formed along the edges of thefabric panel. The loop containing the plastic rod is then inserted intothe groove in the frame followed by an elongated molded strip thatcreates a wedge to trap the fabric and the rod inside the frame. Themolded strip that contains the wedge forms an outer surface of thegroove once it is inserted into the frame. The slot opening formed bythe wedge and the frame is smaller than the rod and therefore the fabriccannot come out unless the wedge is removed. The wedge is locked inplace by an interference created by a lip in the wedge and an undercutmolded into the frame.

[0012] The assembly process starts by first installing the rod into thefabric hem, then inserting an edge of the fabric into the frame andimmediately followed by pushing the wedge behind the fabric. Thisprocess is performed in a sequential manner along the perimeter of theframe until all of the fabric is trapped in the frame. The wedge has atendency to snap into the frame as the wedge strip registers into theslot. Additional space in the interior of the frame provides room forthe rod to move aside as the wedge is pushed into the slot as itregisters in place.

[0013] The retention method of the present invention has a self-lockingfeature in that the greater the tension on the fabric, the greater theforce holding the wedge in the frame. The force created by the rodattempting to come out of the slot pushes laterally against the wedge ina manner that increases the interference between the wedge lip and theframe undercut.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a perspective view of an upholstered chair according theprinciples of the present invention; and

[0015]FIG. 2 is a cross-sectional view of the frame structure showingthe retention method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Referring the drawings, FIG. 1 illustrates one example of anupholstered outdoor patio chair 10 constructed in accordance with theprinciples of this invention. The chair consists of a metal framestructure 12 to which a woven synthetic material 14 is attached. Othercommon upholstery fabric materials can also be used. The chair framestructure comprises a plurality of sections. A first frame member 16begins at a first ground engaging end 18 and extends vertically to formthe left front leg 20 of the chair. The first frame section continuesthen having a first bend and extends rearwardly forming the left armrest 22. The first frame section continues and is bent downwardly to asecond grounding engaging end 24 to form the left rear leg 26. A secondframe member 28 begins at a third ground engaging end 30 and extendsvertically to form the right front leg 32 of the chair. The second framesection continues, then having a first bend and extends rearwardlyforming the right arm rest 34. The second frame section continues and isbent downwardly to a fourth ground engaging end 36 to form the rightrear leg 38. Horizontal front support member 40 extends between and iswelded to the left and right front legs. Horizontal lower back supportmember 42 extends between and is welded to the back legs. A secondhorizontal upper back support member 44 extends between the rear of theleft and right arm rests for further support.

[0017] Finally, the frame structure consists of a seating surface framemember 46 which comprises a left side 48, a right side 50 and top andbottom sides 52 and 54 respectively. The seating surface frame member 46is attached between the first frame section 16 and the second framesection 28. Although chair 10 is depicted with a particular design, itis to be understood that the chair can comprise many different designs.

[0018] Preferably the entire frame structure, but at least the framestructure to which flexible seating material is to be connectedcomprises a continuous configuration preferably made of any aluminumextrusion with three internal hollow channels spaced apart and runningparallel throughout the entire length of the sections as seen best inFIG. 2. The frame section 12 includes internal hollow channels 60, 62and 64. Channel 60 and 62 is divided by support member 66 and channels62 and 64 are divided by support member 68. Support members 66 and 68extend from an outer surface 70 and an opposite outer surface 72 of theframe member 12. The hollow channels provide the frame section with alight weight feature along with greater flexibility. Channel 64 has aslot 78 molded on one surface. Slot or groove 78 is formed as part ofthe extension.

[0019] The chair frame is upholstered with a woven material 14 which iscut into a panel or panels as necessary for a particular design. Eachedge 74 of the fabric seating material which is to be retained withinthe chair frame is folded over and stitched 76 to form an elongated loop77 along the perimeter of the seat panel. Other methods can be used toform loops on the edge of the fabric such as heat sealing, sonicwelding, etc.

[0020] As shown in FIG. 2, groove or slot 78 extends into hollow channel64. It is to be understood that depending on the specific design of thechair, groove 78 could extend into any one of the hollow channels in theframe member. Preferably the frame structure is assembled such that thegroove runs along the inside surface or underside of the frame member toprovide an aesthetically appealing appearance. However, slot 78 can beformed in any surface of the frame.

[0021] The seat panel is attached to the frame by placing a rod 80 intothe loop 77 formed in the fabric material 14. The rod 80 can be flexibleor rigid depending upon the designed configuration of the specific chairbut has a diameter that is less than the width of groove 78. The edge ofthe fabric material 14 having the loop and the rod is then inserted intothe channel 78 along with an elongated molded strip 82. Elongated moldedstrip 82 can be flexible or rigid again depending upon the designconfiguration of the specific chair, but includes a wedge portion 84 anda top portion 86. The wedge portion 84 includes an angled surface 85 anda flat surface 87. The elongated molded strip including the wedge ispushed behind the fabric immediately after being inserted into thechannel 64 to lock the fabric within the channel. This process isperformed in a sequential manner along the perimeter of the frame untilall of the fabric is trapped in the frame. The wedge has tendency tosnap into the frame, as the lip on the wedge passes the undercut of theframe, as the wedge strip is pushed into the slot. The wedge 84 islocked into place by an interference created by a lip 88 formed in theframe along the edge of the groove 78. The lip 88 forms an undercutmolded into the frame. Top portion 86 of the molded strip is flush withthe top surface 70 of the frame member upon insertion.

[0022] In the assembled condition, the fabric and rod is trapped in theframe cavity by the wedge preventing the fabric from pulling out offrame. The slot opening formed by the wedge and the frame is smallerthan the rod and therefore the fabric cannot come out unless the wedgeis removed. The wedge has a tendency to snap and lock into the frame asthe wedge strip is pushed into the slot. The additional space in channel64 provides space for the fabric and rod to move aside as the wedge ispushed into the slot as it registers into the frame.

[0023] The retention method has self-locking feature in that the greaterthe tension on the fabric, the greater the force holding the wedge inthe frame. The lateral force created by the rod attempting to come outof the slot pushes against the wedge in a manner that increases theinterference between the flat surface 87 of the wedge portion 84 and thelip 88 in the frame. The angled surface 85 also is forced against anangled surface 89 of support member 68. To remove the fabric from theframe, the wedge can be pulled out of the slot relaxing the tension onthe fabric or with simple tools that push the rod into cavity 64allowing the fabric to be easily removed from the frame.

[0024] The present invention does not require a secondary means to puttension on the fabric. The process of assembly allows and facilitatesthe creation of tension in the material as it is being assembled intothe frame. Up to four sides can be attached along the surface of theframe. The wedge shape has a tendency to roll the fabric into the framewhile in tension. This method simplifies the construction of the framewith a result in lower manufacturing costs compared to prior methods.Without the need for a secondary tensioning mechanism, the retentionmethod of the present invention allows for a rigid frame to be buildwhere the fabric can be captured around the full perimeter. As a result,the fabric can take on contours that are not possible using prior fabricattachment methods. The present method allows for the fabric to beinstalled on the frame along the surface along any point along theperimeter instead of just at the end of the extrusion as with priormethods.

[0025] The present invention has been described with respect to apreferred embodiment thereof, however other modifications can be made inthe invention without departing from the scope of the invention. Forexample, other alternatives to using a rod on the perimeter of thefabric can be utilized such as sewing any type of round material on theperimeter of the fabric pattern, similar to a cushion welting. Themethod can also be adapted to a variety of applications that requireretaining a flexible material in a frame structure. It need not belimited to seating applications, for example, stretching a materialaround a frame to serve as a vertical panel or screen or for decorativepurposes. These and other aspects of the invention can be furtherunderstood by referring to the invention as hereinafter claimed.Although the invention has been illustrated with respect to a patiochair, it is equally applicable to other furniture items such as forexample, chaise lounge chairs, tables, ottomans, etc.

What is claimed is:
 1. An upholstered patio chair comprising: a metalframe structure of compound three-dimensional shape including a backsection, a seating section and two side sections with at least oneinternal hollow channel extending along at least a portion of a lengthof the frame structure; an elongated groove located in the framestructure opening into the hollow channel and forming a lip portion inthe frame structure; at least one fabric panel for upholstering at leastone of the back section, seating section or side sections of the metalframe structure, the fabric panel having at least one edge containing aloop which extends through the elongated groove and into the hollowchannel of the frame structure; and an elongated wedge member forsecuring the loop of the fabric panel to the frame structure in thechannel such that the fabric panel smoothly maintains the compoundthree-dimensional shape of the frame structure, the wedge member ismaintained in the channel by an interference fit between the wedgemember and the lip portion in the frame structure.
 2. The chair of claim1 wherein the wedge member has a top portion and a flat surface adjacentthe top portion and angled surface adjacent the flat surface.
 3. Thechair of claim 2 wherein the top portion of the wedge member is flushwith the frame structure when the wedge member is inserted into theelongated groove.
 4. The chair of claim 2 wherein the hollow channel hasan angled surface and the interference fit between the wedge member andthe frame structure occurs when the flat surface contacts the lipportion and the angled surface of the wedge portion contacts the angledsurface of the channel.
 5. The chair of claim 1 wherein the rod isinserted into the loop.
 6. The chair of claim 1 wherein the groove has awidth greater than a width of the loop.
 7. A furniture item comprising:a metal frame having a hollow interior and a groove extending throughthe frame into the hollow interior, the frame has an angled surface inthe hollow interior and a lip adjacent the groove and the angledsurface; a flexible fabric surface having a peripheral edge portionextending into the hollow interior of the metal frame through thegroove; and a wedge member retaining the peripheral edge portion in thehollow interior by forming an interference fit with the lip and theangled surface of the frame.
 8. The furniture item of claim 7 whereinthe wedge has a top portion and a flat surface adjacent the top portionand an angled surface adjacent the flat surface.
 9. The furniture itemof claim 8 wherein the top portion of the wedge member is flush with themetal frame when the wedge member is inserted into the groove.
 10. Thefurniture item of claim 7 wherein a rod is inserted into a loop formedin the peripheral edge portion of the flexible fabric surface.
 11. Amethod of upholstering an outdoor patio furniture item made of metalframe members having a hollow interior comprising the steps of: forminga groove in the metal frame members such that the groove extends intothe hollow interior of the metal frame members and forms a lip in themetal frame members; forming a loop along a peripheral portion of aflexible fabric surface; and retaining the flexible fabric surface inthe hollow interior in the metal frame members by inserting the loopalong with an elongated molded strip containing a wedge portion into thegroove of the metal frame members thereby registering the wedge portioninto an interference fit with the lip portion of the metal frame member.12. The method of claim 11 wherein a rod is inserted into the loop ofthe flexible fabric surface prior to insertion through the groove.